Blackjack is a popular card game typically played in a casino. It is also known by the names “twenty-one” and “pontoon” in British English. It is descended from the card game “vingt-et-un” (trans. “twenty-one”), which originated in French casinos during the 18th century. In the original, there was no bonus paid out for a two-card hand totaling 21 points.
Rules of Blackjack
Blackjack hands are scored according to the point total of the cards in the hand. The hand with the highest total wins as long as it is 21 or less. If the total is greater than 21, it is a called a “bust.” Numbered cards 2 through 10 have a point value equal to their face value, and face cards (i.e., Jack, Queen and King) are worth 10 points. An Ace is worth 11 points unless it would bust a hand, in which case it is worth 1 point. Players play against the dealer and win by having a higher point total no greater than 21. If the player busts, the player loses, even if the dealer also busts. If the player and dealer have hands with the same point value, this is called a “push,” and neither party wins the hand.
After the initial bets are placed, the dealer deals the cards, either from one or more, but typically two, hand-held decks of cards, or from a “shoe” containing multiple decks of cards, generally at least four decks of cards, and typically many more. A game in which the deck or decks of cards are hand-held is known as a “pitch” game. “Pitch” games are generally not played in casinos. When playing with more than one deck, the decks are shuffled together in order to make it more difficult to remember which cards have been dealt and which have not. The dealer deals two cards to each player and to himself. Typically, one of the dealer's two cards is dealt face-up so that all players can see it, and the other is face down. The face-down card is called the “hole card.” In a European variation, the “hole card” is dealt after all the players' cards are dealt and their hands have been played. The players' cards are dealt face up from a shoe and face down if it is a “pitch” game.
A two-card hand with a point value of 21 (i.e., an Ace and a face card or a 10) is called a “Blackjack” or a “natural” and wins automatically. A player with a “natural” is conventionally paid 3:2 on his bet, although in 2003 some Las Vegas casinos began paying 6:5, typically in games with only a single deck.
Once the first two cards have been dealt to each player and the dealer, the dealer wins automatically if the dealer has a “natural” and the player does not. If the player has a “natural” and the dealer does not, the player automatically wins. If the dealer and player both have a “natural,” neither party wins the hand.
If neither side has a “natural,” each player completely plays out their hand; when all players have finished, the dealer plays his hand.
The playing of the hand typically involves a combination of four possible actions “hitting,” “standing,” “doubling down,” or “splitting” his hand. Often another action called “surrendering” is added. To “hit” is to take another card. To “stand” is to take no more cards. To “double down” is to double the wager, take precisely one more card and then “stand.” When a player has identical value cards, such as a pair of 8s, the player can “split” by placing an additional wager and playing each card as the first card in two new hands. To “surrender” is to forfeit half the player's bet and give up his hand. “Surrender” is not an option in most casino games of Blackjack. A player's turn ends if he “stands,” “busts” or “doubles down.” If the player “busts,” he loses even if the dealer subsequently busts. This is the house advantage.
After all players have played their hands, the dealer then reveals the dealer's hole card and plays his hand. According to house rules (the prevalent casino rules), the dealer must hit until he has a point total of at least 17, regardless of what the players have. In most casinos, the dealer must also hit on a “soft” 17 (e.g., an Ace and 6). In a casino, the Blackjack table felt is marked to indicate if the dealer hits or stands on a soft 17. If the dealer busts, all remaining players win. Bets are normally paid out at odds of 1:1.
Four of the common rule variations are one card split Aces, early surrender, late surrender and double-down restrictions. In the first variation, one card is dealt on each Ace and the player's turn is over. In the second, the player has the option to surrender before the dealer checks for Blackjack. In the third, the player has the option to surrender after the dealer checks for Blackjack. In the fourth, doubling-down is only permitted for certain card combinations.
Insurance
Insurance is a commonly-offered betting option in which the player can hedge his bet by wagering that the dealer will win the hand. If the dealer's “up card” is an Ace, the player is offered the option of buying Insurance before the dealer checks his “hole card.” If the player wishes to take Insurance, the player can bet an amount up to half that of his original bet. The Insurance bet is placed separately on a special portion of the table, which is usually marked with the words “Insurance Pays 2:1.” The player buying Insurance is betting that the dealer's “hole card” is one with a value of 10 (i.e., a 10, Jack, Queen or King). Because the dealer's up card is an Ace, the player who buys Insurance is betting that the dealer has a “natural.”
If the player originally bets $10 and the dealer shows an Ace, the player can buy Insurance by betting up to $5. Suppose the player makes a $5 Insurance bet and the player's hand with the two cards dealt to him totals 19. If the dealer's hole card is revealed to be a 10 after the Insurance betting period is over (the dealer checks for a “natural” before the players play their hands), the player loses his original $10 bet, but he wins the $5 Insurance bet at odds of 2:1, winning $10 and therefore breaking even. In the same situation, if the dealer's hole card is not one with a value of ten, the player immediately loses his $5 Insurance bet. But if the player chooses to stand on 19, and if the dealer's hand has a total value less than 19, at the end of the dealer's turn, the player wins his original $10 bet, making a net profit of $5. In the same situation, if the dealer's hole card is not one with a value of ten, again the player will immediately loser their $5 Insurance bet, and if the dealer's hand has a total value greater than the player's at the end of both of their turns, for example the player stood on 19 and the dealer ended his turn with 20, the player loses both his original $10 bet and his $5 Insurance bet.
Basic Strategy
As in all casino games, the house has a statistical advantage over the players so that the house nets a predictable percentage over an infinite number of hands, and gets closer to that percentage as the number of hands approaches infinity. However, unlike games in which the player makes no decisions except with respect to the bet, Blackjack players can reduce the casino advantage by several means, the most elementary of which is “basic strategy.” “Basic strategy” is simply something that exists as a matter of general practice; it has no official sanction. The “basic strategy” determines when to hit and when to stand, as well as when doubling down or splitting in the best course. Basic strategy is based on the player's point total and the dealer's visible card. Under the most favorable conditions (i.e., playing with a single deck according to downtown Las Vegas rules) the house advantage over a player using basic strategy can be as low as 0.16%. Casinos offering options like surrender and double-after-split may be giving the player using basic strategy a statistical advantage and instead rely on players making mistakes to provide a house advantage.
A number of optional rules can benefit a skilled player, for example: if doubling down is permitted on any two-card hand other than a natural; if “doubling down” is permitted after splitting; if early surrender (forfeiting half the bet against a face or Ace up card before the dealer checks for Blackjack) is permitted; if late surrender is permitted; if re-splitting Aces is permitted (splitting when the player has more than two cards in their hand, and has just been dealt a second ace in their hand); if drawing more than one card against a split Ace is permitted; if five or more cards with a total no more than 21 is an automatic win (referred to as “Charlies”).
Other optional rules can be detrimental to a skilled player. For example: if a “natural” pays less than 3:2 (e.g., Las Vegas Strip single-deck Blackjack paying out at 6:5 for a “natural”); if a hand can only be split once (is re-splitting possible for other than aces); if doubling down is restricted to certain totals (e.g., 9–11 or 10–11); if Aces may not be re-split; if the rules are those of “no-peek” (or European) Blackjack, according to which the player loses hands that have been split or “doubled down” to a dealer who has a “natural’(because the dealer does not check for this automatically winning hand until the players had played their hands); if the player loses ties with the dealer, instead of pushing where neither the player or the dealer wins and the player retains their original bet.
Card Counting
Unlike casino games like roulette and craps, in which one play has no influence on any subsequent play, a hand of Blackjack removes those cards from the deck. As cards are removed from the deck, the probability of each of the remaining cards being dealt is altered (and dealing the same cards becomes impossible). If the remaining cards have an elevated proportion of 10-value cards and Aces, the player is more likely to be dealt a natural, which is to the player's advantage (because the dealer wins even money when the dealer has a natural, while the player wins at odds of 3:2 when the player has a natural). If the remaining cards have an elevated proportion of low-value cards, such as 4s, 5s and 6s, the player is more likely to bust, which is to the dealer's advantage (because if the player busts, the dealer wins even if the dealer later busts).
The house advantage in Blackjack is relatively small at the outset. By keeping track of which cards have been dealt, a player can take advantage of the changing proportions of the remaining cards by betting higher amounts when there is an elevated proportion of 10-value cards and Aces and by better lower amounts when there is an elevated proportion of low-value cards. Over time, the deck will be unfavorable to the player more often than it is favorable, but by adjusting the amounts that he bets, the player can overcome that inherent disadvantage. The player can also use this information to refine basic strategy. For instance, basic strategy calls for hitting on a 16 when the dealer's up card is a 10, but if the player knows that the deck has a disproportionately small number of low-value cards remaining, the odds may be altered in favor of standing on the 16.
There are a number of card-counting schemes, all dependent for their efficacy on the player's ability to remember either a simplified or detailed tally of the cards that have been played. The more detailed the tally, the more accurate it is, but the harder it is to remember. Although card counting is not illegal, casinos will eject or ban successful card counters if they are detected.
Shuffle tracking is a more obscure, and difficult, method of attempting to shift the odds in favor of the player. The player attempts to track groups of cards during the play of a multi-deck shoe, follow them through the shuffle, and then looks for the same group to reappear from the new shoe, playing and betting accordingly.
Casino Countermeasures
The basic method of thwarting card counters is to use a large number of decks. Shoes containing 6 or 8 decks are common. The more cards there are, the less variation there is in the proportions of the remaining cards and the harder it is to count them. The player's advantage can also be reduced by shuffling the cards more frequently, but this reduces the amount of time that can be devoting to actual play and therefore reduces the casino profits. Some casinos now use shuffling machines, some of which shuffle one set of cards while another is in play, while others continuously shuffle the cards. The distractions of the gaming floor environment and complimentary alcoholic beverages also act to thwart card counters. The simplest way of thwarting card counting is the inferior Blackjack payoff of 6:5, which even with a single deck is statistically much more disadvantageous to the player than standard 3:2 Blackjack.